COMPOSITION OF FOOD AND ACTION OF ENZYMES. 



685 



active enzyme at the moment of secretion, or it may be secreted in 

 inactive form and require the co-operation of some other substance 

 before it is capable of effecting its normal reaction. In such cases the 

 second substance is said to activate the enzyme. An example is 

 found in the case of the trypsin of the pancreatic secretion. 



PARTIAL LIST OF THE ENZYMES CONCERNED IN THE PROC- 

 ESSES OF DIGESTION AND NUTRITION. 



ENZYME. 



( Ptyalin (sali- 

 vary diastase. 



Amylopsin 

 (pancreatic 

 diastase). 



Liver diastase. 



Muscle diastase. 



o3 -j Invertase. 



I s ! 



Maltase. 



Lactase. 

 Glycolytic? 



Lipase (steap- 

 sin). 



f Pepsin. 

 Trypsin. 



Erepsin. 



Group of auto- 

 lytic enzymes. 



WHERE CHIEFLY 

 FOUND. 



Salivary secretion. 



Pancreatic secre- 

 tion. 



Liver. 



Muscles. 



Small intestine. 



Small intestine, 

 salivary and 

 pancreatic se- 

 cretion. 



Small intestine. 



Muscles? 



Pancreatic secre- 

 tion, fat tissues, 

 blood, etc. 



Gastric juice. 



Pancreatic juice. 



ACTION. 



Converts starch to sugar 



(maltose). 

 Converts starch to sugar 



(maltose). 



Converts glycogen to dex- 

 trose. 



Converts glycogen to dex- 

 trose. 



Converts cane-sugar to 

 dextrose and levulose. 



Converts maltose to dex- 

 trose. 



Converts lactose to dex- 

 trose and galactose. 



Splits and oxidizes dex- 

 trose. 



Splits neutral fats to fatty 

 acids and glycerin. 



Converts proteins to pep- 

 tones and proteoses. 



Splits proteins into sim- 

 pler crystalline prod- 

 ucts. 



Splits peptones into sim- 

 pler products. 



Splits proteins into nitrog- 

 enous bases and amino- 

 bodies. 



Converts guanin to xan- 

 thin by splitting off an 

 NH 2 group as ammonia 

 (NH 3 ). 



Converts adenin to hypo- 

 xanthin by splitting off 

 an NH 2 group as am- 

 monia (NH 3 ). 



Causes oxidation of organ- 

 ic substances, as in the 

 conversion of hypoxan- 

 thin to xanthin and of 

 xanthin to uric acid. 



Decomposes hydrogen 

 peroxid. 



Chemical Composition of the Enzymes. It was formerly 

 believed that the enzymes belong to the group of proteins. They 



Guanase. 



, ^ Adenase. 



i 



Oxidases. 



Catalase. 



Small intestine. 

 Tissues generally. 



Thymus, adrenals, 

 pancreas. 



Spleen, pancreas, 

 liver. 



Lungs, liver, mus- 

 cle, etc. 



Many tissues. 



